Al-Qaida Confirms Deputy Leader Killed in US Strike in Syria

Al-Zawahri is believed to be based in the Pakistan-Afghanistan border region, but many of the group's senior figures are believed to have moved to Syria, taking advantage of the country's civil war to establish a presence -- though many of them have subsequently been killed in U.S. drone strikes the past year. An al-Qaida-linked group, Fatah al-Sham, is one of the strongest forces among the rebels fighting to oust Syrian President Bashar Assad.